I don't wear prescription glasses and I've pretty much given up wearing "safety" glasses while cycling because it's mostly nicer not to, but when I do (for instance if it's very cold or in midge season) and it starts to rain, nowadays I take them off anyway. Can't see as much as I'd like with specks on the specs (and if it's raining the flies go away and it won't be quite that cold – usually). Fogging I agree tends to be a temporary problem while stationary. So not much help in my post, sorry, but if anyone does have a cure, I'd like to know. Oh, and plus whatever for the peaked cap – I virtually always have one, against rain, sun, and so much more.